Telegram
60
MA 258
i
Leuze electronic
Bit 3: Copy to transmit buffer: CTB
This bit is only relevant for writing slave data in blocks (Collective mode), see chapter 11.1.2.
Notice!
The state change of the CTB bit signals the MA that the data is going into the buffer; therefore,
it's essential to observe the order!
When the CTB is not used, the telegram (which fits in one cycle) is transmitted directly to
the RS 232 interface. Please make sure it is complete!
10.4
RESET function / deleting memory
For many applications, it is helpful to be able to reset the MA buffer (in Collective mode) or
status bits.
The following bit pattern can be transmitted from the PLC for this purpose (if >20 ms is
pending):
Control byte 0:
10101010 (AAh)
Control byte 1:
10101010 (AAh)
OUT data byte 0/parameter byte 0:
AAh
OUT data byte 1/parameter byte 1:
AAh
This sets the memory or status/control bits to 00h.
Please observe that the data image may need to be updated by toggling in Collective mode.
Output data
Description
Addr.
Data
type
Value range
Default
CTB
C
opy to
t
ransmit
b
uffer
(transmission data to transmit buffer)
Toggle bit: Changing this bit writes the data from the PLC to
the transmit buffer of the fieldbus gateway. This is used, for
example, for long command strings which must be transmit-
ted to the connected ident device.
The CTB toggle bit is switched whenever transmit data is not
to be sent directly via the serial interface, but instead trans-
ferred to the transmit buffer.
1.3
Bit
0->1: Data in buffer
1->0: Data in buffer
0
